Schizophrenia is defined by a lack of a straightforward genetic cause for a very large majority of affected individuals. The prefrontal cortex (PFC), among other brain regions, is thought to be frequently in subjects in schizophrenia, as reflected by its functional hypoactivity and dysregulated expression for a diverse set of genes. The underlying molecular mechanisms remain unknown but there is evidence that the prolonged maturation of the PFC, extending into or even beyond the second decade of life, plays a crucial role for normal human development and the neurobiology of schizophrenia. Recently, we presented the first evidence that a subset of epigenetic markings, including trimethylated histone H3-lysine 4 at sites of gene promoters, is involved in the dynamic regulation of PFC chromatin during throughout pre- and postnatal development, and may be altered in some cases with schizophrenia. This challenge grant proposal is "shovel ready" and create new jobs as well as retain existing ones. Specifically, we will combine two of the most innovative approaches in the field of neurosciences as it pertains to epigenetics, by selectively sorting neuronal chromatin followed by massively parallel sequencing of immunprecipitates (ChIP-seq) to obtain insight into the epigenomic landscape of prefrontal neurons. We will profile developmental and disease-related changes in histone methylation markings associated with active promoters (trimethyl-H3K4) or transcription (trimethyl-H3K36) selectively in PFC neurons. Furthermore, we will study in conditional mutant mice the role of a candidate histone lysine methyltransferase, Mll1 (mixed-lineage leukemia 1) for normal and diseased prefrontal development, by expressing Cre recombinase selectively in weanling PFC and then monitor behavioral and molecular alterations in the adult animal. The experiments proposed here, which are designed to be accomplished within the challenge grant's award period of 24 months, will clarify, for the first time, whether or not chromatin of human PFC neurons is developmentally regulated and altered in disease. The answer to this question on a genome-wide level will be critical in order to find out whether or not chromatin-based mechanisms are part of a final common pathophysiology underlying prefrontal dysfunction in the substantial portion of subjects diagnosed with schizophrenia. PUBLICH HEALTH RELEVANCE: For the majority of patients diagnosed with schizophrenia, no straightforward genetic cause has been identified. One of the important theories about schizophrenia implies that in some brain regions, such as the "prefrontal cortex", a number of genes are not switched on properly during normal development, as they are in healthy subjects. However, until now the molecular techniques to study these phenomena have been lacking. This challenge grant proposal is "shovel ready", will create new jobs and retain existing ones. It is also based on extremely innovative techniques that were recently developed in our laboratories. We were able, for the first time, to selectively isolate chromosomal materials and chromatin from the nerve cells of the human brain obtained postmortem, and study "epigenetic markings" (basically, chemical modifications that regulate gene expression and function without altering the genetic code) on a genome-wide level. In this proposal, we plan to examine epigenetic gene activation patterns during normal prefrontal cortex development and search for potential alterations in schizophrenia and in mutant mice designed to model the disease on a molecular level. This research should clarify whether or not epigenetic markings are dynamically regulated in human neuronal chromatin , and if major psychiatric diseases such as schizophrenia are associated with changes in the neuronal epigenome.